Implantable superelastic anastomosis device

ABSTRACT

A one piece anastomosis device is disclosed which is formed of a superelastic or pseudoelastic material which self deforms or self deploys from an insertion configuration to a tissue holding configuration. The device in a deployed state preferably includes an inner tissue penetrating flange which penetrate and retains an everted graft vessel and an outer flange. The self deploying anastomosis device does not rely on a temperature transformation to achieve deployment.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to an implantable medical device such as ananastomosis device and a deployment system for implanting the device. Ina preferred embodiment, the device can be used for forming a suturelessconnection between a bypass graft and a blood vessel.

[0003] 2. Brief Description of the Related Art

[0004] Vascular anastomosis is a procedure by which two blood vesselswithin a patient are surgically joined together. Vascular anastomosis isperformed during treatment of a variety of conditions including coronaryartery disease, diseases of the great and peripheral vessels, organtransplantation, and trauma. In coronary artery disease (CAD) anocclusion or stenosis in a coronary artery interferes with blood flow tothe heart muscle. Treatment of CAD involves the grafting of a vessel inthe form of a prosthesis or harvested artery or vein to reroute bloodflow around the occlusion and restore adequate blood flow to the heartmuscle. This treatment is known as coronary artery bypass grafting(CABG).

[0005] In the conventional CABG, a large incision is made in the chestand the sternum is sawed in half to allow access to the heart. Inaddition, a heart lung machine is used to circulate the patient's bloodso that the heart can be stopped and the anastomosis can be performed.During this procedure, the aorta is clamped which can lead to trauma ofthe aortic tissue and/or dislodge plaque emboli, both of which increasethe likelihood of neurological complications. In order to minimize thetrauma to the patient induced by conventional CABG, less invasivetechniques have been developed in which the surgery is performed throughsmall incisions in the patients chest with the aid of visualizingscopes. Less invasive CABG can be performed on a beating or stoppedheart and thus may avoid the need for cardiopulmonary bypass.

[0006] In both conventional and less invasive CABG procedures, thesurgeon has to suture one end of the graft vessel to the coronary arteryand the other end of the graft vessel to a blood supplying vein orartery. The suturing process is a time consuming and difficult procedurerequiring a high level of surgical skill. In order to perform thesuturing of the graft to the coronary artery and the blood supplyingartery the surgeon must have relatively unobstructed access to theanastomosis site within the patient. In the less invasive surgicalapproaches, some of the major coronary arteries including the ascendingaorta cannot be easily reached by the surgeon because of their location.This makes suturing either difficult or impossible for some coronaryartery sites. In addition, some target vessels, such as heavilycalcified coronary vessels, vessels having very small diameter, andpreviously bypassed vessels may make the suturing process difficult orimpossible.

[0007] Accordingly, it would be desirable to provide a suturelessvascular anastomosis device which easily connects a graft to a targetvessel. It would also be desirable to provide a sutureless anastomosisdevice which is formed of one piece and is secured to the target vesselin a single step.

SUMMARY OF THE INVENTION

[0008] A superelastic or pseudoelastic one piece anastomosis deviceaccording to the present invention connects a graft vessel to a targetvessel. The anastomosis device deforms from an insertion configurationto a tissue holding configuration due to the superelastic orpseudoelastic properties of the material.

[0009] In accordance with one aspect of the present invention, a onepiece anastomosis device for connecting a graft vessel to a targetvessel includes a device body formed of a superelastic or pseudoelasticmaterial. The device body has an insertion configuration and a tissueholding configuration in which the body has an inner flange and an outerflange. At least one of the inner and outer flanges is radiallyconstrained in the insertion configuration for insertion into the targetvessel. When the device body is released it self deforms to the tissueholding configuration.

[0010] In accordance with another aspect of the present invention, atube deployed anastomosis system for connecting a graft vessel to atarget vessel includes a deployment tube and an anastomosis deviceformed of a superelastic or pseudoelastic material. The device has aninsertion configuration and a tissue holding configuration in which thedevice has an inner flange and an outer flange. The inner and outerflanges are radially constrained in the deployment tube in the insertionconfiguration for insertion into the target vessel and when releasedfrom the deployment tube, the device self deforms to the tissue holdingconfiguration.

[0011] In accordance with another further aspect of the presentinvention, a method of deploying an anastomosis system for connecting agraft vessel to a target vessel includes the steps of: connecting agraft vessel to a one piece device formed of a superelastic orpseudoelastic material; poking a portion of the one piece device throughthe graft vessel; and deploying the one piece device by self deformationto a tissue holding configuration in which the device has an innerflange and an outer flange and traps the target vessel tissue betweenthe inner flange and the outer flange.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The invention will now be described in greater detail withreference to the preferred embodiments illustrated in the accompanyingdrawings, in which like elements bear like reference numerals, andwherein:

[0013]FIG. 1 is a perspective view of a first embodiment of ananastomosis device in a constrained configuration prior to use;

[0014]FIG. 2 is a perspective view of the anastomosis device of FIG. 1in a deployed configuration;

[0015]FIG. 3 is a side cross sectional view of the anastomosis device ofFIG. 1 with a graft vessel everted around the device and the deviceconstrained by a tube prior to deployment;

[0016]FIG. 4 a side cross sectional view of the system of FIG. 3 beinginserted into a target vessel:

[0017]FIG. 5 is a side cross sectional view of the system of FIG. 3after release of an inner flange;

[0018]FIG. 6 is a side cross sectional view of the system of FIG. 3 withthe inner flange imbedded in an inner wall of the target vessel wall;

[0019]FIG. 7 is a side cross sectional view of the system of FIG. 3after release of the outer flange showing the deployment tube beingremoved;

[0020]FIG. 8 is a perspective view of an alternative embodiment of ananastomosis device in a constrained configuration prior to use;

[0021]FIG. 9 is a perspective view of the anastomosis device of FIG. 8in a deployed configuration;

[0022]FIG. 10 is side cross sectional view of the anastomosis device ofFIG. 8 after deployment shown connecting a graft and a target vessel;

[0023]FIG. 11 is a perspective view of an alternative embodiment of ananastomosis device in a constrained configuration prior to use;

[0024]FIG. 12 is a perspective view of the anastomosis device of FIG. 11in a deployed configuration;

[0025]FIG. 13 is a side cross sectional view of the anastomosis deviceof FIG. 11 after deployment shown connecting a graft vessel to a targetvessel;

[0026]FIG. 14 is a perspective view of an alternative embodiment of ananastomosis device in a constrained configuration prior to use;

[0027]FIG. 15 is a perspective view of the anastomosis device of FIG. 14in a deployed configuration;

[0028]FIG. 16 is a perspective view of an alternative embodiment of anexpandable body anastomosis device in a constrained configuration priorto use; and

[0029]FIG. 17 is a perspective view of the anastomosis device of FIG. 16in a deployed configuration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] The present invention relates to a superelastic or pseudoelasticanastomosis device and method for connecting a graft vessel to a targetvessel without the use of conventional sutures. The quick and easydeployment of the anastomosis system according to the present inventiongreatly increases the speed with which anastomosis can be performed overthe known sutured anastomosis methods. The anastomosis devices accordingto the present invention are particularly designed for use in connectinggraft vessels to target vessel in a variety of anastomosis procedures,including coronary artery bypass grafting. In such procedures, a largevessel anastomotic device is used to connect a graft vessel to largediameter target vessels such as the aorta or it's major side branchesand a small vessel anastomotic device is used for connecting a graftvessel to a target vessel having a small diameter such as a coronaryartery.

[0031] Suturing a graft vessel to a target vessel with conventionalprocedures is difficult and time consuming, particularly in minimallyinvasive procedures where space may be limited and in procedures inwhich it may be desired to perform an anastomosis without stoppage ofblood flow through the target vessel. The superelastic or pseudoelasticanastomosis device and method of the present invention allow anastomosisto be performed efficiently and effectively in tight spaces. Theanastomosis may also be performed with or without stoppage of blood flowin a target vessel and with or without the use of cardiopulmonarybypass.

[0032]FIG. 1 illustrates an anastomosis device 10 according to a firstembodiment of the present invention in a constrained insertionconfiguration in which the anastomosis device would be inserted into atarget blood vessel. FIG. 2 illustrates the anastomosis device 10 ofFIG. 1 in an expanded deployed configuration which holds a graft vesselto a target vessel. The superelastic or the pseudoelastic anastomosisdevice in FIG. 1 includes a substantially cylindrical body 14, aplurality of legs 16 extending from a first side of the body, and aplurality of hooks 18 extended from a second side of the body. In theinsertion configuration illustrated in FIG. 1, the body 14, the legs 16,and the hooks 18, are substantially aligned in a constrainedsubstantially cylindrical shape. The anastomosis device 10 may be heldin the constrained substantially cylindrical shape by a deployment tool,such as a substantially cylindrical deployment tube. When the deploymenttool is removed from the device 10, the device returns to a presetexpanded shape illustrated in FIG. 2 due to the superelastic orpseudoelastic properties of the material.

[0033] The anastomosis device 10 is made of a pseudoelastic orsuperelastic alloy, such as Nitenol or other pseudoelastic orsuperelastic material. The superelastic or pseudoelastic device 10 willself deform through superelastic or pseudoelastic behavior from theconstrained insertion configuration illustrated in FIG. 1 to theexpanded configuration illustrated in FIG. 2 when the constrainingdevice or deployment tool is removed. The anastomosis device 10 formedof the superelastic or pseudoelastic material is formed in the finalshape illustrated in FIG. 2 and is then isothermally deformed byconstraining in a tube or other deployment tool in the substantiallycylindrical shape illustrated in FIG. 1. The need for temperaturecontrol is avoided since the anastomosis device 10 reforms the deployedshape of FIG. 2 spontaneously when removed from the constraining tube.This allows the accurate placement of the anastomosis device 10spontaneous and nearly instantaneously upon deployment of the device.The need for a mechanical deployment device to mechanically deform theanastomosis device from the insertion configuration to the deployedconfiguration is also avoided.

[0034] The anastomosis devices of the present invention may be made ofany known superelastic or pseudoelastic material. U.S. Pat. No.5,597,378 provides a discussion of superelastic and pseudoelasticmaterials and is incorporated herein by reference in its entirety.

[0035] The deployed anastomosis device 10 as shown in FIG. 2 includes aninner flange formed by outwardly extruding ends 22 of the J-shaped hooks18. The deployed device 10 also includes an outer flange formed by thelegs 16 extending outward from the body 14.

[0036] In use, a graft vessel 30, shown in FIG. 3, is threaded through acenter of the anastomosis device 10. An end 34 of the graft vessel 30 iseverted around the hooks 18 and the hook ends 22 penetrate into orthrough the everted end 34 of the graft vessel retaining the graftvessel in place on the anastomosis device 10.

[0037] As illustrated in FIG. 3, the anastomosis device 10 with theeverted graft vessel 30 is positioned within a deployment tube 38 fordelivery of the anastomosis device and graft vessel to an opening 40 ina target vessel 32. In the radially constrained insertion configuration,the leading edge or hook end of the anastomosis device may besubstantially cylindrical or slightly conical for ease of insertion.

[0038] One embodiment of a method for deploying the anastomosis device10 of the present invention will be described with reference to FIGS.3-6. As shown in FIG. 3, the graft vessel 30 is prepared by everting anend 34 of the graft vessel around the hooks 18 of the anastomosis device10. The hook ends 22 penetrate the graft vessel tissue to maintain theeverted configuration of the graft vessel. The hooks 18 and the legs 16of the anastomosis device 10 are radially constrained by inserting theanastomosis device 10 and everted end of the graft vessel 30 into adeployment tool 38 in the shape of a tube. When positioned inside thedeployment tool 38, the anastomosis device 10 is in a generallycylindrical configuration for insertion into the target vessel 32.

[0039] As shown in FIG. 4, the deployment tool 38 is used to insert theanastomosis device 10 and the graft vessel 30 into the target vessel 32until the hook ends 22 have passed through the opening 40 and arepositioned within an interior of the blood vessel. As shown in FIGS. 3and 4, a retainer tube 36 is positioned around the graft vessel 30 andinside the deployment tool 38 for holding and extruding the anastomosisdevice 10. A distal end 48 of the retainer tube 46 is positionedadjacent to a proximal end of the anastomosis device 10. The distal end48 of the retainer tube 46 may be attached to or abut the anastomosisdevice 10 to hold the anastomosis device in place inside the deploymenttube 38 during the insertion step of FIG. 4.

[0040] As shown in FIG. 5, the anastomosis device 10 is held in place bythe retainer tube 46 while the deployment tube 38 is withdrawn orretracted to release the radial constraining force from the hooks 18.Upon removal of the deployment tube 38 from the hooks 18, the hook ends22 and hook base portion 24 spontaneously spring outward due to thesuperelasticity or pseudoelasticity of the material.

[0041] As shown in FIG. 6, after the release of the hooks 18 theanastomosis device 10 is withdrawn by the deployment tool 38 against theinterior wall of the target vessel 32 causing the hook ends 22 to becompressed against or penetrate into the tissue of the interior wall ofthe target vessel. The deployment tube 38 is then completely withdrawnas shown in FIG. 7 allowing the legs 16 to spontaneously spring outwardto trap the wall of the target vessel 32 between the hooks 18 which forman inner flange and the legs 16 which form an outer flange for thedeployed anastomosis device 10.

[0042] FIGS. 8-10 illustrate an alternative embodiment of an anastomosisdevice 50 having a central body portion 54. A first set of legs 56extend from one end of the body 54 and a second set of pointed legs 58extend from the second side of the body. In a constrained configurationillustrated in FIG. 8, the anastomosis device 50 is substantiallytubular for insertion into a target vessel. In an expanded deployedconfiguration, illustrated in FIGS. 9 and 10, the anastomosis device 50is substantially C-shaped in cross section with the legs 56 forming anouter flange and the pointed legs 58 forming an inner flange of theanastomosis device 50.

[0043] The embodiment shown in FIGS. 8-10 may be deployed in a mannersimilar to that of the anastomosis device described above with respectto FIGS. 1-7. As shown in FIG. 10, the graft vessel 62 is everted aroundthe anastomosis device 50. The anastomosis device 50 and graft vessel 62are then inserted into an opening in the target vessel 64 in aconstrained configuration. A constraining device such as the deploymenttool 38 is then removed from the anastomosis device 50 and graft vessel62 allowing the legs 56 and 58 to spontaneously spring outward by thesuperelastic or pseudoelastic properties of the material to form innerand outer flanges which trap the tissue of the target vessel 64 betweenthe inner and outer flanges.

[0044] According to one preferred embodiment of the anastomosis device50 the pointed legs 58 each include a pointed tissue penetrating end 66and a rectangular stop member 68 for limiting the tissue penetration ofthe penetrating end. As shown in FIG. 10, the tissue penetrating end 66of the pointed legs 58 penetrates into or through the graft vessel 62 toensure the graft vessel is retained on the anastomosis device 50 duringand after deployment.

[0045] In the deployed configuration illustrated in FIG. 10, the intimaof the graft vessel 62 abuts an intima of the target vessel 64. Thus,the expansion of the inner flange of the anastomosis device 50 forms avein gasket to seal the graft and target vessels together.

[0046] FIGS. 11-13 illustrate an alternative embodiment of thesuperelastic or pseudoelastic anastomosis device 80 in a radiallyconstrained configuration illustrated in FIG. 11 and in an expandedtissue retaining configuration illustrated in FIGS. 12 and 13. Theanastomosis device 80 includes a device body 84 formed of a plurality ofsubstantially parallel spring elements 86 interconnecting to end members88. Extending from the end members 88 are a plurality of prongs 90 whichin the expanded tissue supporting configuration illustrated in FIG. 13,form inner and outer flanges to trap the tissue of the target vessel 96.As in the previous embodiments, a graft vessel 94 is inserted through acenter of the anastomosis device body 84 and is everted around theprongs 90 of at least one end the device body. The prongs 90 penetrateinto or through the graft vessel tissue to retain the graft vessel onthe anastomosis device.

[0047] The anastomosis device 80 with the graft vessel 94 everted aroundthe anastomosis device is inserted in a radially constrainedconfiguration illustrated in FIG. 11 into an opening in the targetvessel 96. When the radially constraining member such as a retainer tubeis removed from the anastomosis device 80, the anastomosis devicespontaneously self deforms and returns to the configuration of FIG. 12due to the superelastic or pseudoelastic properties of the material.

[0048] As shown in FIG. 13, a first set of the prongs 90 forms a flangeat the inner wall of the target vessel. The spring elements 86 allow thedistance between the end members 88 to adjust somewhat to target vessels96 having walls of different thicknesses. The spring elements 86 mayalso apply a compression force to the wall of the target vessel 96 oncethe anastomosis device 80 has been deployed to provide improved sealing.

[0049] In an alternate embodiment of the anastomosis device 80 of FIGS.11-13, the graft vessel 94 may be attached to the anastomosis devicewithout everting. This may be done by providing axial prongs, hooks, orbarbs on the inner rail member 88 and hooking an end of the graft vesselon the hooks, prongs, or barbs without everting.

[0050] An alternative embodiment of an anastomosis device 100 includesan anastomosis device body 104, legs 106, and hooks 108, as in theembodiment of FIGS. 1 and 2. The embodiment of FIGS. 14 and 15 differsfrom the embodiment of FIGS. 1 and 2 in that the legs 106 are foldedoutward and downward adjacent the body 104 in the radially constrainedinsertion configuration illustrated in FIG. 14. The legs 106 willspontaneously spring out to the flange forming configuration of FIG. 15when the radially constraining member such as a retainer tube is removedfor deployment of the anastomosis device 100.

[0051]FIGS. 16 and 17 illustrate an alternative embodiment of ananastomosis device 200 including a device body 204, legs 206 and pointedlegs 208. The body 204 is formed of axially extending members 210interconnected by struts 212 which allow the body to expand radially.Positioned between the body 204 and the pointed legs 208 are hinges 214.FIG. 16 illustrates the anastomosis device 200 in a radially constrainedinsertion configuration with a graft vessel 220 extending through aninterior of the device body 204 and everted over the pointed legs 208.The pointed legs 208 penetrate and hold the everted end of the graftvessel 220 on the device 200.

[0052] For insertion, the anastomosis device 200 of FIG. 16 is radiallyconstrained in a deployment tube (not shown). As the deployment tube iswithdrawn from the device 200, the pointed legs 208 fold outward to forman inner flange, the device body 204 expands radially, and the legs 206fold outward to form an outer flange. The radially expanding body 204helps to stretch and support an opening in the target vessel.

[0053] Each of the anastomosis devices according to the presentinvention are preferably single piece devices which are formed in asubstantially tubular shape. The anastomosis devices may be formed bylaser cutting or punching from a tube or sheet of superelastic orpseudoelastic material. Alternatively, the devices may be formed fromsuperelastic or pseudoelastic wire. The devices may be provided invarying sizes to join vessels of different sizes. The legs, hooks,prongs, and other device elements which have been discussed above withregard to the various embodiments may be used in varying numbers andarrangements depending on the particular application.

[0054] The invention has been described as an anastomosis device whichis constrained for insertion in a radially constrained configurationwith a deployment tool such as tube. However, the deployment tube maytake other non-tubular shapes.

[0055] Although the invention has been primarily discussed with respectto coronary artery bypass surgery, the anastomosis devices of thepresent invention may by used in other types of anastomosis procedures.For example, the anastomosis device may be used in femoral-femoralbypass, vascular shunts, subclavian-carotid bypass, organ transplants,and the like. The devices according to the present invention may be usedwith venous grafts such as a harvested saphenous vein graft, arterialgraft, such as a dissected mammal artery, or a synthetic prosthesis, asrequired.

[0056] Finally, the anastomosis devices according to the presentinvention have been illustrated as substantially cylindrical members.However, the devices can also be shaped into ovals, football shapes, orother shapes. Oval shapes can be particularly useful for accommodatingsmall target vessels.

[0057] While the invention has been described in detail with referenceto the preferred embodiments thereof, it will be apparent to one skilledin the art that various changes and modifications can be made andequivalents employed, without departing from the present invention.

What is claimed is:
 1. A one piece anastomosis device for connecting agraft vessel to a target vessel comprising: a device body formed of asuperelastic or pseudoelastic material, the body having an insertionconfiguration and a tissue holding configuration in which the body hasan inner flange and an outer flange, wherein at least one of the innerand outer flanges is radially constrained in the insertion configurationfor insertion into the target vessel and when released self deforms tothe tissue holding configuration.
 2. The device of claim 1, wherein aportion of the device body between the inner flange and the outer flangeis expandable from a first diameter insertion configuration to a seconddiameter tissue holding configuration.
 3. The device of claim 1, whereinthe superelastic or pseudoelastic material is a nickel titanium alloy.4. The device of claim 1, further comprising a plurality of tissuepenetrating elements for penetrating and holding a graft vessel in placeon the device body.
 5. The device of claim 4, wherein the tissuepenetrating elements are formed on one of the inner and outer flanges.6. The device of claim 4, wherein the tissue penetrating elements extendradially outwardly from the device body for holding an everted end ofthe graft vessel.
 7. The device of claim 1, wherein the device body usesthe superelastic or pseudoelastic properties of the material to selfdeform from the insertion configuration to the tissue holdingconfiguration.
 8. A tube deployed anastomosis system for connecting agraft vessel to a target vessel comprising: a deployment tube; and ananastomosis device formed of a superelastic or pseudoelastic material,the device having an insertion configuration and a tissue holdingconfiguration in which the device has an inner flange and an outerflange, wherein the inner and outer flanges are radially constrained inthe deployment tube in the insertion configuration for insertion intothe target vessel and when released from the deployment tube, the deviceself deforms to the tissue holding configuration.
 9. The device of claim8, wherein a portion of the device body between the inner flange and theouter flange is expandable from a first diameter insertion configurationto a second diameter tissue holding configuration.
 10. The device ofclaim 8, wherein the superelastic or pseudoelastic material is a nickeltitanium alloy.
 11. The device of claim 8, further comprising aplurality of tissue penetrating elements for penetrating and holding agraft vessel in place on the device body.
 12. The device of claim 11,wherein the tissue penetrating elements extend radially outwardly fromthe device body for holding an everted end of the graft vessel.
 13. Thedevice of claim 8, wherein the device body uses the superelastic orpseudoelastic properties of the material to self deform from theinsertion configuration to the tissue holding configuration.
 14. Amethod of deploying an anastomosis system for connecting a graft vesselto a target vessel, the method comprising: connecting a graft vessel toa one piece device formed of a superelastic or pseudoelastic material;poking a portion of the one piece device through the graft vessel; anddeploying the one piece device by self deformation to a tissue holdingconfiguration in which the device has an inner flange and an outerflange and traps the target vessel tissue between the inner flange andthe outer flange.
 15. The method of claim 14, wherein the one piecedevice is deployed by removing a radially constraining deployment toolfrom the device.
 16. The method of claim 15, wherein the deployment toolis a deployment tube which receives the tubular device, and wherein thedeployment tube is inserted partially into the target vessel wall andthen withdrawn to deploy the one piece device from the deployment tube.17. The method of claim 14, wherein the one-piece device is deployed byemploying the superelastic or pseudoelastic property of a superelasticor pseudoelastic material from which the one piece device is formed. 18.The method of claim 14, wherein the graft vessel is everted around theone piece device.
 19. The method of claim 14, wherein the deployed onepiece device abuts an intima of the graft vessel against an intima ofthe target vessel.